Electric switch



1,537,472 c. Y. KNIGHT ELECTRIC swncn May 12, 1925.

Filed Dec. 6, 1923 Patented Ma y 1925.

UNITED STATES PATENT 1,537,472 "OFFICE. j

CHARLES Y. KNIGHT, or orncnco, ILLINOIS, AssIenoR To nnmurm's & Jonas con.- romrrom'or DETROIT, MICHIGAN, A CORPORATION or NEW YORK.

ELECTRIC SWITCH.

To all whom it may concern:

.Be it known that I, CHARLES Y.- KNIGHT,

citizenof the United States, residing at Chicago, Illinois, have invented'certain new and useful Improvements in an Electric Switch; and I do hereby declare the follow- 1 ing to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the. same. My invention relates to electric switches of the so-called single-pole type, and in general aims to provide an unusually inexpensive,. compact and durable switch of this class. In one of its more particular objects, my invention aims to provide a switch in which a yieldingly mounted circuit-closing element I larged head at its. forward end and the head 7 forms part of a slidably mounted switching member, in which the yielding pressure is I provided by a spring through which no currentpasses, in which the circuit-closing element continuously engages one of the contact terminals of the switch and is latched in either its on or .off position by riding over a hump on this contact terminal, in

which the circuit-closing is effected by, the

= bridging of a plunger-tip across the gap between two contact termmals, and in which simple and effective means are provided for preventing the switching member as a whole from rotating.

Still further and also more detailed ob- ;jects'will appear from the following specification and from the accompanying draw ings, in which Fi 1 is a front elevation of an electric switc embodying my invention.

Fig. 2 is an enlarged section taken through the same switch centrally and transverse of its face, this being taken with the switching member in its circuit-exposed closing or on position.

Fig.3 is a section similar to a portion of Fig. 2, but showing the switching member in its circuit-opening or off position.

Fig. 4 is a section taken along thev line 4-4 of Fig. 2.

Fig. 5 isa perspective view of the digitally movable button'which forms the exposed head of the movable switching member, showing the inward projection on this button which is engaged by walls of a slot to prevent the button from rotating? In the embodiment of the drawings, the

switch of my invention comprises a cylindrical casing 1 provided at its forward end with ears 2, which ears are secured in any suitable manner to a face plate 3. This face plate forms the front of the switch and closes the forward end of the casing, while the rear endof the cylinder 1 is closed by an insulating disk 4 which forms the 'base of the switch. I

Extending through and clinched to this insulating base 4 are a pair of hollow rivets 5 and 6, ,each of which is threaded for receiving' one of the screws 7 and 8 as employed respectively for clamping the ends of the two circuit wires 9 and'10 to the said form portions ofthe circuit terminals.

Each-of these hollow rivets has an en- 7o hollow rivets, so that these hollow rivets I tion 15 formed from it and disposed Within the said recess 12 to afford a contact terminaladapted to be engaged by the switching member of the switch.

The face plate 3 of the switch has a slot 16 extending in the same general direction as the channel-skated contact portion 15 of the said plate and disposed with the center of the 'slot'opposite the center of this contact portion, so as to form a guide for the movable switching member 1 hereafter described. Extending into this slot 16 is a portion 17 on the back of a button 18 which is exposed on the front of the face plate 3, this extension 17 being in the form of a boss 17 having flat sides engaging the side walls of the slot 16 so as to keep the button from rotating in this slot. The button 18 serves as a slidab'le support for-a cylinder 19 which has a shank 2O threaded into the back of the button 18. An insulating washer 21 is in-, terposed between the back of the face plate 3 and the forward. end of this cylinder 19, but the boss 17 engages this washer and is of a length greater than the thickness of the face plate 3, so as to prevent the screwing of the shank 20 into the button from clamping the face plate tightly between the washer as a carrier for a plunger having a head 22 slidably fitting the bore of the cylinder and continuously pressed forward' by a spring 23. This plunger has a stem 24 projecting beyond-the rear end of the cylinder and continuously engaging the channel or contact portion of the said circuit terminal.

lVith the parts thus arranged, the cylinder 19 together with its spring-pressed plunger and with its shank .20 extending through the slot in the face-plate and with the insulating parts 21 and 18 disposed at opposite sides of this plate forms a bodily movable switching member which can freely be slid longitudinally of the said slot so as to move the spring-pressed plunger 24 along the channel 15. The spring 19 maintains the tip of the plunger continuously in engagement with the channel 15 and this channel de sirablyis forwardly bowed so as to present a hump which will exert a cam action tending to hold the switching member either in its lowermost position (or off) of Fig. 2

or in its uppermost (or on) position in Fig. 3. When in the former position, the plunger also. contacts with the head 11 of the rivet 5, thereby bridging the gap between this head and the metal channel and hence closing the circuit connection between the wires 9 and 10. \Vhcn the switching member is in its uppermost position as shown in Fig. 3, the plunger is out ofengagement with the lower rivet, thereby opening the circuit.

By thus bowing the bottom of the channel 15 so as to form a hump over which the plunger rides, I cause the switch to give a slight snap when moved in either direction,

and in practice this snapping action is some what augmented by the usual looseness of the fit of the plunger head 22 within the cylinder 19. Consequently, my novel switch construction. affords a positive throw-over for the switching member whenever this is moved in either direction. Since the circuit terminal plate comprising the parts 14 and 15' is a simple punching and since the hollow rivets as well as the cylinder and .plunger are cheaply made screw machine products, my entire switch is low in cost.

Moreover, the continuous spring-pressed bearing of the plunger against the channel 15 and'its intermittent bearing agamst the head 11 of one of the hollow rivets keeps the contacting parts clean by a wiping ac-.-

tion, so that I can readily secure the desired ample conductivity. Y

However, while I'have illustrated and described my invention in an embodiment having'certain highly desirable shapes and ar rangements of the various parts, I do not wish to be limited to these or other details of the construction and arrangement thus disclosed, itbeing obvious that many modifications might be made without departing tending through the slot of the switch front and slidable upon the switch front, the switching member having a conducting portion continuously engaging the said plate portion and yieldingly pressed toward the latter and movable by a sliding of the switching member with respect to the switch front-into and out of a position in which it also engages the said overhanging wire terminal head.

2. A switch as per claim 1, in which the circuit terminal plate includes a part secured to one circuit terminal and another part ofi'set froni the aforesaid part and housed by the recess in the insulating base,

the latter part having a portion bowed toward the switch front so as to afford a. hump over which the conducting portion of the switching member rides while being moved into and out of its said position, the said hump affording a cam action cooperating with the yielding pressing of the said conducting portion. towards the said plate to hold the switching member in either of two positions in only one of which it engages the overhanging wire terminal head.

3. A switch as per claim 1, in which the circuit terminal plate comprises a portion resting upon the forward face ofthe insu lating plate and secured to one of the wire terminals, and a channel shaped portion extending into the'said recess, the channel shaped portion including a pair of walls laterallyengaging the conducting portion of the switching member to'prevent movement of the said portion transversely of the said longitudinal plane of the recess, and also engaging the longitudinal walls of the recess to prevent rotation of the said plate about the said wire terminal. I

4. A switch comprisinga casing having a slot in its front and a back of insulating material parallel to the front, a pair of circuit terminals having portions exposed on the forward face'of the said back and spaced from each 'other in a direction longitudinal of the slot; and a switching member comprising a pair of 'insulating elements respectively engaging the forward and rear faces of the said front, the forward one of the said elements havin a shank extendiir into the slot and this shank having flat walls enelement, a metal plunger extending through gaging the longitudinal walls of the slot to the opening of the cylinder, and a spring in prevent rotation of the shank with respect the cylinder continuously urging-the plunger 10 to the said front; a I rearwardly open ,cylrearwardly.

' a inder having a forwardly directed threaded Signed at Chicago, Illinois, Deoember3rd,

stem extending through the rear'one of the 1923. said elements and threaded into the forward CHARLES Y. KNIGHT. 

